Mechanical stoker



K. USUI MEGHANCAL STOKER Filed Nov. l5 1919 3 Sheets-Sheet l sept. 4, 1923.

K. USUl MECHANICAL sToKER 3 Sheets-Sheet 2 Filed Nov. l5 1919 TOR/VE) Sept. 4, 1923. mam K. Usui MECHANICAL STOKER 5 ASheets-Sheet 3 Filed Nov. l5 1919 I "1 l1N VENTO/e By m? Q@ 5W/NN f4 Y lllllllllll Illlllllllllll l a ll- Patented Sept. 4, 1923.

KIrcnrRo UsUr, or sHrzUoKA-KEN, Jaren.

MECHANICAL STOKER.

Application filed November 15, 1919. Serial No. f.$38,203.

To all whom t may con-cera.'

Be it known that I, KUCHIRO Usui., a subject of the Emperor of Japan,- and a resident of No. 169 Minami-f'kndo. Toyoda, Abe- Gun, ShiZuoka-Ken, Empire of Japan, have invented new and useful Improvements in Mechanical Stokers, of 'which the following is a specification.

This invention relates to improvements in mechanical stoke'rs of the type in which the grate bars move from end to end, the object of the invention being to yprovide an improved stoker of this type embodying' novel means for successively dropping` the grate bars at the rear end of the grate and for carrying them forwardly and reinstating them for use at the front end of the grate, andalso .embodying means of novel construction for regulating the draft of air under and between the grate bars. y

lith the above and other objects inl View the invention resides in the construction, combination and arrangement of parts hereinafter described and claimed.

In the accompanying drawings 4 Fig. l is a central longitudinal sectional elevation of a preferred form of mechanical. stoker in accordance with my invention.

Fig. la is al similar view of the rear portion of the grate. l

Fig. 2 is a front elevatiompartly in section, on the plane indicated by the line 2 2 of Fig. 1.

Fig. 3 is a transverse section taken on the plane indicated by the line 3 3 of Fig. 1.

-Fig 4 isa detail perspective view of a portion of one form ofgrate bar.

Fig. 4a is a similarfview of a portion of another modified form of grate bar.

Fig. 4b is a 'similar'view another modified form of grate bar.

Fig. 4t is a similar lview of a portion of still another modified form of the same.

Similar reference numerals refer to like parts throughout the several views.

Automatic stokers may be generally di4 vided int-o two classes.y one in' which the fire grate is arranged in the form of anendless movable chain, and the other in which the grate barsgmove back and forth longitudinally of the furnace. The former while possessing better feeding eiiiciency of the fuel often has defects necessitating frequent repairing. The.' latter while requiring 'no yfre- *B in Fig. 4e,

of a portion of `thereby causing quent repairing has heretoforefbeen not satisfactory as to the feeding of the; fuel.

lV ith the object of removing the difficulties experienced with both classes of the stokers above referred to, and yet obtaining the full advantages 'attached thereto. l have invented a Stoker hereinafter described which fwill work satisfactorily and which .combines the advantages possessed by both such classes of stokers.

lThe, combustion chamber of the furnace is not here shown.` It may occupy the space indicated atv l., The stoker is supported from underneath by two opposin'ggirdcrs 2, the lower ends of which rest upon suitable rollers 3 adapted to move back and forth upon a corresponding railway l, in order to facilitate cleaning and repairingl when required. V

`In some instances, mounted upon rollers or y 2 may be conveniently secured to the side wall of the combustion chamber or otherwise rigidly secured to the flue for instance,V of the Cornish or Lancashire boilers.

Upon the inner opposing walls of thegirders 2, at the upper portions thereof, are secured stationary rails 5 adapted'to receive thereon a set of grate bars, the'constructionl instead of being wheels, each girder of which bars 6 may vary according to the nature of the fuels, for instance y1n cases` in which coal is used asV fuel in a combustion chamber of considerable breadth, preferably a bar, such as shown in Fig. 4 at A, having' al serrated portion between the spaced ribs so as to secure kbetter ventilationmay be employed; Other forms such as `shown ator at C in Fig. 4b, or at'D in Fig 4c, may be employed, according to coni ditions. l y 'A A Bar conveying means are provided which consist of a set of reciprocating rails 7 arranged under the stationary rails 5, and which are mounted on suitable rollers 19.l `Ter-tical plates 8 having inclined front ends, are secured to the rear ends of the' recipro# eating rails 7 and extending forwardly'and downwardly from the rear ends of the Stationary *railsy 5 afford the means for receiving on said inclined front ends the grate bar dropped from the rear end of the lire grate, the *said bars to slide down along the said inclined ends of theplates 8 and to' rest on the rear portion of .the horif Zontal ribs of the conveyor rails 17 which are secured to the girders 2, and positioned above the reciprocating rails 7.

At the fro-nt end portion of each reciprocating rail 7 is provided a lever 9, the lower end of which is fitted with a. suitable roller 10 adapted to engage with and capable of sliding back and forth upon the roller track 12 by means of a link 11 which is pivotally connected with and extends between the re ciprocating rails 7 and the roller 10, as shown in Fig. 1.

The action is such that in the downward movement the upper end of the lever 9 will be placed in position ready to receive thereon the grate bars shifted from the conveyor' rails 17, whilst in the upward movement this lever 9 will assume the position adapted to raise the grate bars and deliver them in succession on to the stationary rails 5, as will appear later.

The means for reciprocating the rails 7 may be any suitable transmission mechanism which may be conveniently arranged in the front portion of the apparatus, the description of which will appear later, and which may be operable through the medium of' a connecting rod 13 extending between and connecting the lower part of each reciprocating rail 7 and the said transmission mech-y anism so as to cause the. latter rail 7 to move back and forth, thereby communicating the motion to cause the lever 9 to be elevated or depressed over the roller rack 12, thus etlfecting the receiving and delivering of the grate bars between the reciprocating rails 7 and stationary rail 5.

The transmission mechanism may be arranged in any suitable manner, and in the drawings I have shown by way of example a shaft 14 adapted to operate the connecting rods 13 through the medium of intermediate gearing such as worms, worm wheels, cranks, etc., as will be necessary to produce the above effect.

To cause the elevated gratevbar to be transferred from the cam levers 9 onto the stationary rails 5 there are provided thrust rods 16 adapted to move back and forth by means of cams 15, likewise operable through the medium of the Same aforesaid transmission mechanism.

The grate bars which drop from the rearmos't end of the lire grate and which lodge upon the rear end of the reciprocating rails 7 after sliding down the slant faces of the inclined plates 8, are conveyed forward one after another successively and step-by-step.

To this end there are provided underneath the stationary rails 5 or otherwise pivoted to the web portions of the same, a plurality vof pawl members 1 7 equally spaced, and inclined downwardly and forwardly so that the free lower end of each member 17 may, at a certain angle, bear upon the upper side of the horizontal webs of the conveyor rails 17.

The reciprocating rails 7 are likewise provided at intervals with a plurality of inclined plates 18, by which the grate bars are enabled to move forward one after another simultaneously with the forward movement of the reciprocating rails 7, action being transmitted from the connecting rods 13. The operation is such that upon the backward movement of the reciprocating rails 7, all the grate bars with which the lower free ends of the pawl members 17 engage are caused to remain stationary upon the conveyor rail 17 allowing the reciprocating rails 7 alone to move backward, whilst upon the forward or return movement of the reciprocating rails 7 all the grate bars with which the front edges 18 of the inclined plates 18 engage are caused to move forward by lifting above them the free ends of the pawl members 17 simultaneously with the movement of the reciprocating rails 7 so as to allow each of 'the grate b-ars to traverse the distance corresponding to the space between the pawl members 117 at the completion of one reciprocating movement of the reciprocating rails 7.

It will be understood that as each grate bar reaches the front ends of the conveyor rails 17 it will be above and in the paths of the levers 9, so thatr said levers in their ensuing forward upward movement will raise said grate bar to the required position above the rails 5 and said grate bar will be pushed in place on said rails 5'by the rods 16. This' will cause the rearmost lire bar to be dropped from the rear end of the grate, thence sliding down along the slant face of the inclined plates 8 until eventually deposited at the front of the rearmost inclined plate 18. Upon the following forward movement of the reciprocating rails 7 the grate bar so positioned at the front of the rearmost inclined plate 18 will be then pushed forward by the frontedge ofthe rearmost inclined plate 18 so as to occupy the position adjacently preceding 'the rearmost pawl members 17', and so on, as will be readily understood.

The feeding of the fuel may be effected through the hopper 19 located above the front end of the fire grate, regulated by a suitable adjustable door 2O through which an appropriate quantity of the fuel is allowed to pass into the front end of the fire grate.

The means for regulating the draft of the air may comprise a plurality of dampers 22 which are preferably pivoted to lthe lower part of the stationary rails 5 and connected by a connecting rod 23. Said rod is connected at one end with the oscillating lever 24. An actuating rod 26 is connected as at 25 to the said oscillating lever 24: and enables the lever 24 to be moved as required to elevate or depress the dampers 22, thus relqfulatingr the draft.

That I claim is In a. mechanical Stoker, supporting rails, grate bars mounted for sliding movement on said rails, conveyor'rails arranged below the su'porting rails, elements at the rear ends of the 'supporting` and conveyor rails, presentingz,` downwardly and forwardly inclined surfaces to cause grate bars, as they successively leave the rear ends of the supporting rails to he directed by said inclined surfaces downwardly and forwardly onto the rear portions of the conveyor rails, downwardly and forwardly inclined pivoted pawls bearing at their lower ends on said conveyor rails, a reciprocating element having plates with inclined upper sides, to facilitate the passage of grate bars thereover and on the forward strokes of said element to engage and move the dropped grate bars forwardly, step-by-step, means at the front ends of the supporting and conveyor bars, to successively raise the grate bars from the conveyor bars, and means to Jforce the raised grate bars rearwardly on the supporting bars.

l In testimony whereof I aiiX my signature in presence of two Witnesses.

KIICHIRO USUI. Witnesses:

HARVEY F. OL'rMAUs, H. YOSUMURA. 

